乳腺癌术后胸壁电子线放射治疗加等效膜对肺组织损伤的影响

目的:探讨不同厚度加组织等效膜(简称加膜)对乳腺癌术后胸壁电子线照射时肺组织放射性损伤的影响。方法:通过以仿真人体组织等效模型所拟的典型成年女子左侧乳腺癌术后患者进行模拟照射,以6M eV电子线照射加不同厚度组织等效膜的仿真人体组织等效模型所拟的体表,用热释光剂量仪进行实际测量;通过动物实验,比较加不同厚度组织等效膜(0.5 cm和1.0 cm厚)对电子线胸壁照射时肺组织的放射性损伤的特点。结果:在无膜及体表加盖0.5、1.0 cm组织等效膜后,6M eV电子线照射时肺前缘的平均受照剂量减少,分别为63.7、30.7、13.4 cGy;同时动物实验表明在无膜及体表加盖0.5、1.0 cm组织等效膜后,无膜组肺组织病理炎性反应最重,加盖0.5 cm厚膜组次之,加盖1.0 cm厚膜组最轻。结论:在体表加盖不同厚度的组织等效膜后,随着等效膜厚度增加,肺前缘受照剂量减少,同时高剂量坪区向表皮移动幅度更大,可以通过增加一定厚度的等效膜来提高整个靶区治疗的剂量要求,同时肺前缘的受照剂量减少,保护了肺组织,从而减少了放射性肺炎的发生。

Influence of lung radiation injury in breast cancer radiotherapy using different depth tissue equivalent boluses on chest wall

Objective To probe the specification of lung injury in breast radiotherapy by different depth using tissue equivalent boluses on chest wall.Method The paper simulated the dose distribution of women's left breast cancer after radical mastectomy by 6MeV electron beam irradiation,and applied TLD to measure.By animal experiments,the influence of lung in electron beam radiotherapy by different depth using tissue equivalent boluses on chest wall was constrasted.Results Adding the bolus depth,the dose of lung became lower;no bolus,0.5cm and 1.0cm bolus above the body,they were 63.7,30.7 and 13.4 cGy.By animal experiments:when using no bolus,0.5cm and 1.0cm bolus above the body,with no bolus the pathological inflammation reaction of lung tissue was heaviest under the elecmicrocope,0.5cm depth bolus was lighter,and 1.0 cm depth bolus was the lightest.Conclusion The dose of anterior margin of lung becomes less when using 0.5cm and 1.0cm bolus above the body;the high dose field moves to surface of the body,and its widen is larger when the bolus is thicker.Using certain depth bolus may attain target area therapy dose,chest wall local control rate is increased,and its relapse rate is decreased and protecting lung tissue,occurrence of radiation pneumonia possibility is reduced.